Over 40,000 children are born with congenital heart defects (CHD) each year in the United States. Improvements in survival have dramatically reduced early mortality, but there are significant gaps in what we know about the psychosocial development of survivors and the mechanisms of risk that account for key social, academic, and emotional outcomes. Most research has focused on the neurodevelopmental and behavioral deficits of very young children with CHD, and there is growing evidence that difficulties in emotional functioning emerge during adolescence. By comparison, we know relatively little about the nature and timing of deficits in other domains impacted by neurodevelopmental risk, such as social competence, during middle childhood and adolescence. Consequently, there is a critical need for longitudinal research that uses rigorous methods to evaluate changes in social, academic, and emotional functioning of CHD survivors across development to inform the timing and targets of new interventions. Our long-term goal is to reduce psychosocial morbidity and improve quality of life for survivors of CHD across the lifespan. The objective of this proposal is to conduct a longitudinal evaluation of social, academic, and emotional functioning in critical CHD survivors across the transition from elementary to middle school. Using a rigorous, multi-method, multi-informant design, we will assess the peer, teacher and self-report of social behavior, acceptance, and friendships in the 4th and 5th grade classrooms of 180 children with critical CHD. Neurocognitive, academic, emotional, and family function will be assessed 1:1 during home visits with CHD survivors and demographically matched comparison classmates (CC). Assessments of developmental progress and protective factors in the family and school environment will be repeated after two years, following the transition to middle school. We will examine factors that explain variability in outcomes amongst CHD survivors as well as differences between CHD survivors and comparison classmates. This will capture risk associated with CHD-specific as well as general developmental processes. Our premise is that poor academic performance and negative peer experiences (e.g., isolation, victimization, rejection, few friendships) contribute to the emergence of internalizing problems in CHD, but this risk will be mitigated by resources (e.g., facilitative parenting and socialization of coping, teacher and parent support) that could be targeted by novel interventions. This work is guided by the following aims. AIM 1: Compare changes in social, academic, and emotional functioning for children with critical CHD and CC across the transition from elementary to middle school, as well as examine predictive associations across these domains for CHD vs CC. AIM 2: Identify individual and environmental resources that account for impairment or buffer deterioration in academic, social, and emotional functioning over time for CHD survivors vs.CC. AIM 3: Identify CHD-specific medical risks (CHD type, treatment, perioperative complications) and environmental resources that explain variability amongst CHD survivors in social, academic, and emotional functioning over time.